HARMONI at ELT: optical design of the spectrograph sub-system

Eduard Muslimov; Matthias Teczaa Edgar Castillo-Dominguez; James Kariuki; Liam Bolanda; Miriam Cisneros-Gonzalez; Kieran McCall; Sophie Paszynska

arXiv · 2607.21264

HARMONI at ELT: optical design of the spectrograph sub-system

Eduard Muslimov·Matthias Teczaa Edgar Castillo-Dominguez·James Kariuki·Liam Bolanda·Miriam Cisneros-Gonzalez·Kieran McCall·Sophie Paszynska

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Abstract

HARMONI is an adaptive optics assisted, near infrared integral field spectrograph for the European Extremely Large Telescope. It covers a spectral range from 750 nm to 2450 nm with resolving powers from 3000 to 7000 and spatial sampling of 25 mas and 6 mas. It can operate in two adaptive optics modes, SCAO and MCAO. The spectrograph represents the last optical sub-system of the HARMONI instrument optical train that disperses the light and forms a two-dimensional spectrogram on its scientific detectors. Changes in the top-level goals and specifications have led to a significant revision of the spectrograph optical design. The current baseline design consists of a two-mirror unobscured collimator, a set of six volume-phase holographic grisms, and a two-mirror unobscured camera. The design is more compact than the previous version, it uses anamorphic freeform mirrors to correct aberrations, and is expected to reach a minimum transmission 57% with improved accessibility of the detector unit and reduced scattered light.

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BibTeX RIS

Eduard Muslimov, Matthias Teczaa Edgar Castillo-Dominguez, James Kariuki, Liam Bolanda, Miriam Cisneros-Gonzalez, Kieran McCall, Sophie Paszynska. 2026-07-23. HARMONI at ELT: optical design of the spectrograph sub-system. https://arxiv.org/abs/2607.21264

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